A209483 Number of n-bead necklaces labeled with numbers -6..6 allowing reversal, with sum zero and avoiding the patterns z z+1 z+2 and z z-1 z-2.

1, 7, 24, 205, 1702, 16660, 168453, 1778878, 19211780, 211576925, 2364602172, 26755001917

Offset

1,2

Comments

Column 6 of A209485.

Links

Table of n, a(n) for n=1..12.

Example

Some solutions for n=6:
.-6...-4...-4...-4...-4...-5...-3...-5...-5...-5...-5...-6...-2...-2...-2...-6
.-3...-1...-4...-1...-1....0...-2....1...-3...-4....0...-1...-1....0...-2...-4
.-3....3....0....5....1....3...-3...-2...-2....0...-1...-3....1....0....3....3
..1....2...-1...-3...-1...-4...-1...-1...-2....6....5....1....1...-1...-2...-4
..5...-4....6...-2....3....1....4....4....6....4...-1....3...-1...-1...-2....6
..6....4....3....5....2....5....5....3....6...-1....2....6....2....4....5....5

Crossrefs

Sequence in context: A111753 A198055 A012761 * A209342 A203117 A197791

Adjacent sequences: A209480 A209481 A209482 * A209484 A209485 A209486

Keyword

nonn

Author

R. H. Hardin, Mar 09 2012

Status

approved